A jewel-toned beetle could drain the color from much of Wilton's future fall foliage displays. The emerald ash borer is just 40 or so miles away, and as a result New Haven County is on lockdown as far as ash trees and any products from those trees are concerned.

The emerald ash borer was detected for the first time in the state on July 16, and has been identified in Prospect, Bethany, Naugatuck and Beacon Falls. It has decimated ash tree populations in 15 other states in less than a decade, killing more than 30 million as of 2009.

As a precaution, the state is instituting emergency firewood regulations as of Thursday, Aug. 9.

"The intent of the quarantine is to slow the spread of the insect out of New Haven County," said Chris Donnelly, urban forestry coordinator in the Department of Energy and Environmental Protection's Division of Forestry. The quarantine will regulate any movement of ash logs, ash materials, ash nursery stock, and hardwood firewood from within New Haven County to any area outside of New Haven County and will parallel a future federal quarantine.

The firewood regulations would require anyone who is moving firewood anywhere in the state to be able to show where it came from. The regulations are not meant to be onerous, Mr. Donnelly said.

"The idea is to educate people and create an awareness," he said, perhaps of "firewood that may have come from Worcester, Mass., where there is a major outbreak of Asian longhorn beetle," another tree-killing pest, "or Saugerties, N.Y., which is also quarantined."

Mr. Donnelly said the state intends to have an information page on its website by the end of this week. Visit ct.gov/deep/forestry or ct.gov/deep/eab.

"This is a disturbing discovery and one that has the potential for great environmental harm in the state," DEEP Commissioner Daniel C. Esty said of the emerald ash borer's presence here. With more than 22 million ash trees in the state — making up 4% to 15% of the tree canopy, the damage this insect could do is significant.

In Wilton

The emerald ash borer has not been detected as of yet in Wilton, according to Pat Sesto, director of environmental affairs, but there is a trap in Weir Preserve that is monitored by the state.

"The Wilton region is on the state's radar," Ms. Sesto said. "It's been on the radar of the tree committee," she added of the beetle.

While she did not know how many ash trees are in town, she estimated the percentage to be about the same as statewide. Unfortunately, many local ash trees have been killed or compromised by a bacterial infection.

As for protecting the ones that are left, there are some insecticide options available, but scientists say controlling insects that feed under the bark is difficult and this is particularly true in this case because North American ash trees have little natural resistance to the emerald ash borer. A reputable arborist can best advise on a course of action.

Ms. Sesto said the biggest step people can take to prevent its arrival is to be scrupulous in knowing where firewood comes from. Homeowners who take wood from either vacation homes or woodlots elsewhere could unknowingly bring the insect here.

"That's the sort of decision-making that's problematic," she said. Ms. Sesto also added that "kiln-dried firewood isn't necessarily insect-free firewood. The purpose is to dry out the wood, not kill insects. Don't put misguided faith in kiln-dried firewood," she added advising, "the only solution is to buy local."

As for wood chips, Mr. Donnelly of DEEP said he did not think they posed as much of a threat as logs. "Most wood chips would not produce viable adults," he said of the emerald ash borer, except in cases of larvae that get a late start.

The beetle

The emerald ash borer is metallic green in color and approximately one-half inch long and one-eighth inch wide. They lay their eggs under the bark and the larvae eat around the insides of trees, girdling and killing them within one to three years. Adults emerge from the bark leaving a small D-shaped exit hole roughly one-eighth inch in diameter.

This insect is native to Asia and was first discovered in the Detroit, Mich., and Windsor, Ontario, regions of North America in 2002. It may have arrived in wood packing materials. It has since spread through the movement of firewood, solid-wood packing materials, infested ash trees, and by natural flight dispersal.

The insect was discovered in Prospect last month by "watchers," Mr. Donnelly said. These are volunteers who keep an eye on a ground-nesting native wasp (Cerceris fumipennis), which hunts beetles in the family Buprestidae, including the emerald ash borer. The wasp, which does not sting people or pets, hunts the beetle and stings it, and drags it back to its nest hole. The wasp then lays an egg on the beetle and its larvae have a fresh insect to feed on, Mr. Donnelly said. Gruesome but effective.

The wasp watchers catch the wasps with a net and in this case, also caught an emerald ash borer.

Parasitic wasps, Mr. Donnelly said, might be a means to establishing biological controls.

Another indicator of emerald ash borer activity is the presence of woodpeckers, which like to eat them. A large number of woodpeckers drilling into ash trees might indicate further investigation is advised.

"We're not the first to have it," Mr. Donnelly said of the emerald ash borer, and that may help the state get ahead of the curve on curbing future damage.

For more information, visit emeraldashborer.info.